[A]: According to the theory of Lamarck use and disuse caused the increase and decrease in size of organs and environment caused the changes which can be transferred to next generation.
[R]: Modern synthetic theory is also known as Neo-Lamarckism.

Options

A. (a) If both A and R are true and R is the correct explanation of A
B. (b) If both A and R are true but R is not the correct explanation of A
C. (c) If A is true and R is false
D. (d) If both A and R are false

Answer

To solve the assertion-reason question, we will analyze both the assertion (A) and the reason (R) statements step by step.

### Step 1: Analyze the Assertion (A)
The assertion states that according to the theory of Lamarck, use and disuse caused the increase and decrease in the size of organs, and that environmental factors could lead to changes that could be inherited by the next generation.

- **Explanation**: Lamarck's theory, known as the "theory of use and disuse," suggests that organs that are used frequently become stronger and larger (hypertrophy), while those that are not used may diminish or disappear over time. He believed that these acquired traits could be passed on to offspring.

### Step 2: Determine the Truth of the Assertion
- **Truth Value**: The assertion is **true**. Lamarck's ideas about the influence of use and disuse on organ size and the inheritance of acquired characteristics are indeed part of his theory.

### Step 3: Analyze the Reason (R)
The reason states that the modern synthetic theory is also known as Neo-Lamarckism.

- **Explanation**: The modern synthetic theory, also known as Neo-Darwinism, integrates Mendelian genetics with Darwinian evolution. It emphasizes genetic variation and natural selection as the primary mechanisms of evolution, rather than the inheritance of acquired characteristics as suggested by Lamarck.

### Step 4: Determine the Truth of the Reason
- **Truth Value**: The reason is **false**. The modern synthetic theory is not known as Neo-Lamarckism; it is correctly referred to as Neo-Darwinism.

### Step 5: Conclusion
Since the assertion is true and the reason is false, the correct answer to the assertion-reason question is that the assertion is true, and the reason is false.

### Final Answer
The correct option is **C**: Assertion is true, Reason is false.

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